Study of Ancyromonas
as a Possible Ancestor to All Metazoa, Fungi, and Choanoflagellates

Preliminary analysis
of 18S rDNA sequences from the flagellate genus Ancyromonas suggests it
is descended from the specific common ancestor of multicellular metazoa
and fungi. Additional phylogenetically-informative genes from species
of Ancyromonas are being sequenced and analyzed to determine if there
is an extant unicellular ancestor to this group. Morphology and ultrastructure
of Ancyromonas species also are being studied and compared with metazoan
and fungal species to determine the extent of shared characteristics suggestive
of common ancestry. Fluorescent in-situ probe hybridization (FISH) technology
is used to look for undiscovered species of this globally-distributed
genus in an effort to find and culture unique species for this and future
study.

Farida Attar

Medical College of Ohio

Population Biology

0074382

Evolution of Life History
Characters in a Arbovirus

Vesicular Stomatitis
Virus (VSV) has been chosen for this study not only because it is similar
to important human pathogens, e.g., measles, influenza, poliovirus, HIV,
hepatitis A, B and C, but its genomic information is stored in RNA instead
of DNA. RNA replication is error-prone, and therefore many mutations are
constantly produced that allow extremely rapid evolution and offer an
opportunity to study specific aspects of virus evolution and general issues
of population genetics. A combination of comparative, mathematical, experimental,
and molecular studies are being used to ask how the life histories of
parasites adapt to different hosts and how these life history traits and
trade-offs between the traits change in response to natural selection
in the laboratory. The answers will significantly enhance our understanding
of the patterns and diversity of life cycles in parasites.

Daniel Buckley

University of Connecticut

Metabolic Biochemistry

0074404

Anaerobic Methane Oxidizers
in Marine Microbial Mats

Anaerobic methane oxidation
(AMOX), a sink for greenhouse gas methane, is a microbially-mediated process
of global ecological significance. This research investigates the biology
of microorganisms responsible for AMOX in marine microbial mats by using
microelectrodes in conjunction with 16S rRNA-based techniques to monitor
the organisms as they occur in their natural environments. The data acquired
from this research helps to determine if AMOX is mediated by a syntropic
relationship between two microbial groups or by a single microbial group
possessing an unknown biochemical pathway.

Jayna Ditty

Texas A&M University

Metabolic Biochemistry

0074386

Characterization of a Second
Circadian Oscillator in Synechococcus sp. Strain PCC 7942

The single-celled cyanobacterium
Synechococcus sp. srain PCC 7942 has a circadian pacemaker or "clock"
consisting of at least three genes (kaiA, kaiB, and kaiC) that has an
endogenous period of 25 hours. A second mutant clock with a 27.5-hour
period has been shown in the sigC mutant of Synechococcus. While experiments
have shown kaiA in this mutant to oscillate with the 27.5 hour period,
kaiB exhibits the wild-type 25 hour periodicity, leading to the hypothesis
that there is an unforeseen oscillator (UFO) present that is overruled
under wild-type conditions by the master Kai oscillator. This research
physiologically characterizes the 27.5-hour oscillation of strain PCC
7942 by examining its temperature compensation and ability to phase reset.
In addition, the molecular basis of the 27.5-hour UFO and its effects
on synechococcal circadian gene expression is investigated.

Caryn Evilia

Thomas Jefferson University

Biochemistry of Gene Expression

0074388

Elements Required for Protein
Synthesis in Archaea

This research focuses on post-transcriptional
modifications of the archaeon Methanococcus jannaschii. This research
provides an understanding of the role of tRNA modifications in the archaeal
adaptation to extreme environments. A variety of approaches are used to
identify modifications that are important for tRNAs in protein synthesis.
The archaeal mechanism of protein synthesis and its differentiation from
those of Eubacteria and Eukarya will be investigated.

Christine Foreman

Montana State University

Ecosystem Studies

0074372

Microbial linkages among
ecocystem components in the McMurdo Dry Valleys in Antarctica

These valleys provide a unique
environment to study biocomplexity in extreme environments. This research
links microbial community structure and function with physical and biogeochemical
processes in the lakes, streams, and terrestrial systems using a suite
of biochemical and molecular biological techniques.

Sandra Haddad

University of Georgia

Metabolic Biochemistry

0074398

Integrated Studies of Biodegradation
in Rhodococcus and Acinetobacter

This research studies aerobic
biodegradation of aromatic hydrocarbons in Rhodococcus sp. strain 19070
and Acinetobacter sp. strain ADP1 and may facilitate the development of
effective bioremediation strategies. Rhodococcus is an environmentally
important microorganism but is difficult to study because genetic techniques
are not well developed for it; however, Acinetobacter can be used to overcome
this difficulty. Since the first step in environmental degradation of
many pollutants is the cleavage of a benzene ring, the primary focus of
this research is the purification and characterization of the enzyme benzoate
dioxygenase from Rhodococcus. The biodegradative pathway is being elucidated
using mutants and complementation studies.

Cynthia Haseltine

University of California Davis

Microbial Genetics

0074380

Mechanism of Homologous
Recombination in Archaea

This research examines general
recombination mechanisms in the hyperthermophilic archaeal microbe Solfolobus
solfataricus. Functional homologues to eukaryotic recombination proteins
are being heterologously produced and are used to reconstitute archaeal
recombination in-vitro. In-vivo gene disruption and mutant rescue studies
will complement the in-vitro data and demonstrate functional homology
of proteins produced by S. solfataricus to those produced in yeasts. Homologous
recombination is a universal process in which genetic information is exchanged
between separate strands of DNA, introducing new linkages and genetic
sequences.

Karin Jackson

University of Maryland Biotechnology
Inst.

Microbial Genetics

0074397

Role of Gene Control Mechanisms
in Microbial Methane Production

The primary goal of this study
is to identify and characterize the mechanism for genetic regulatory control
of methanogenesis, which has a pivotal role in the global carbon cycle.
A combination of physiological and genetic approaches is being used to
investigate the control networks that mediate expression of a catabolic
gene encoding carbon monoxide dehydrogenase in the methanogen Methanosarcina
actevorans.

Janet Lamb

University of Rochester

Biochemistry of Gene Expression

0074374

Identification of Novel
Pseudomonas aeruginosa Quorum Sensing Genes

Monitoring of surroundings
by quorum sensing in Pseudomonas aeruginosa, a gram-negative bacterium,
plays an important role in its ability to grow in a wide variety of conditions.
The two best studied quorum-sensing systems are the las and rhl systems.
This research utilizes a fluorescence activated cell sorter (FACS)-based
approach to identify novel genes positively and negatively regulated by
the las and/or rhl system. Temporal induction or repression of the identified
genes is examined during the growth cycle, and regulatory factors dictating
the induction and/or repression of these genes are identified. In addition,
the functions of these genes are examined via insertional activation and
observation of the phenotypic changes.

This research seeks to measure
the rate and mode of evolutionary change in Wolbachia, a bacterium that
lives intracellularly in multiple tissues of various arthropods, and identify
the selective forces that mediate persistence of different Wolbachia phenotypic
variants in populations. Specifically, the aims are to address 1. Whether
or not modification and rescue variants of Wolbachia are maintained in
populations as part of an evolutionary cycling scenario, and 2. If the
rate and pattern of Wolbachia evolution suggest a small effective population
size for the symbiont.

Deborah Millikan

University of Hawaii

Animal Development

0074383

Motility-related Symbiotic
Determinants in Vibro fischeri

The interaction between microbe
and host is a dynamic process that requires phenotypic changes by both
partners and likely the coordinated regulation of specific genes for the
success of this association. The symbiotic interaction between the luminous
bacterium Vibrio fischeri and the bobtail squid Euprymna scolopes is a
model system for investigating the role of bacterial motility in the colonization
of animal tissue. While V. fischeri cells present in seawater must be
motile to migrate to the initial site of colonization in the juvenile
squid, a role for motility in the colonization of specific locations within
the animal has not been investigated. This research 1. Experimentally
identifies colonization stage-specific regulation of motility genes and
2. Explores, via two approaches, the ability of V. fischeri to coordinately
regulate motility genes with other colonization factors. The first approach
is to examine symbiotic capacity of V. fischeri mutants that exhibit an
altered motility phenotype, while the second approach is to experimentally
investigate the role of the bacterium's polar flagellum, which is thought
to play a role in gene regulation within the bacteria. The results of
the proposed work will likely serve as a model that provides an improved
understanding of the role of motility and co-regulated symbiotic factors
in bacterial host interactions.

Dale Pelletier

Stanford University

Microbial Genetics

0074387

Molecular Biology of Anaerobic
Ethylbenzene Oxidation

The goal of this research is
to advance the understanding of the processes involved in the microbial
metabolism of aromatic hydrocarbons under anaerobic conditions. Recent
biochemical investigation of anaerobic ethylbenzene degradation with the
denitrifying bacterium Azoarcus sp. strain EB1 has led to a proposed pathway
for ethylbenzene mineralization. DNA microarray analysis and 2-dimensional
gel electrophoresis experiments are used to identify genes differentially
expressed during anaerobic growth of Azoarcus. These experiments will
lead to identification and functional analysis of genes involved in ethylbenzene
mineralization, with special consideration of the gene associated with
ethylbenzene dehydrogenase (a novel enzyme found within Azoarcus which
catalyzes the removal of a hydride from an aromatic hydrocarbon, initiating
anaerobic ethylbenzene oxidation). The genetic tools developed here, in
addition to furthering knowledge of hydrocarbon metabolism, will also
be helpful in identifying environmental factors involved in regulation
of ethylbenzene degradation and will help to maximize the potential use
of these organisms for bioremediation applications.

Daniel Rozen

University of Dundee

Plant & Microbial Development

0074378

Evolution of Morphological
Variation Across Dictyostelid Social Amoebae

While most microbes live solitary
lives, a few groups have evolved more complex multicellular strategies.
The multicellular structures of one such group, the Dictyostelids, are
extremely variable both in size and overall morphology. This work examines
the evolution of morphological diversity across Dictyostelid species using
a comparative approach. Three questions are addressed: To what extent
are mechanisms that affect size and pattern conserved across solitary
amoebas (SA's)? What specific molecular changes underlie the divergent
morphologies observed across SA species? What is the molecular evolutionary
history of genes involved in SA fruiting body size and pattern formation?
This research provides insight into the evolutionary origins of their
morphological variation and begins to address the evolution of these social
organisms from solitary ones.

Elise Sullivan

Rutgers University

Metabolic Biochemistry

0047363

The Use of Benzoyl-CoA Reductase
Genes in the Benzoate Pathway as an Indicator of Anaerobic Bacterial Degradation
of Monoaromatic Hydrocarbon Pollutants

A key feature of monoaromatic
compound metabolism by anaerobic bacteria is the enzyme benzoyl-CoA reductase,
a protein previously thought to be highly conserved among anaerobes. This
research examines the diveristy of this important enzyme. Then, the mechanisms
by which benzoate degradation takes place are being characterized 1. Via
biochemical analysis and 2. Mutagenesis-to determine which genes are involved
in the process. Finally, Terminal Restriction Fragment Length Polymorphism
analysis is being used to determine the abundance and diversity of these
genes in the environment. This study will help assess the appropriateness
of reductase genes as indicators of a bacterial community's capacity for
bioremediation of aromatic hydrocarbons in polluted environments.

David Valentive

Stanford University

Metabolic Biochemistry

0074368

Experimental Studies of
Hydrogen-producing Bacteria

Hydrogen is a key intermediate in anaerobic environments and is maintained
at low concentration by microbial competition. This research uses a novel
hydrogen-removal system to study the physiology and bioenergetics of obligately
hydrogen-producing bacteria in pure culture. Studies focus on metabolism
of important substrates, i.e., acetate, benzoate, amino acids, and glycolate.
Enrichment and isolation procedures for anaerobic bacteria are also being
developed. Hydrogen metabolism in bacteria is not well-understood but
plays an important role in microbial diversity in the environment.

Doyle Ward

University of California Berkeley

Molecular Biochemistry

0074391

Understanding Bacterial
Injection of DNA into Other Cells

The bacterium Agrobacterium
tumefaciens injects DNA into plant cells via a type IV transporter "syringe",
transforming the plant and creating a more favorable habitat for itself.
Type IV transporters are multi-protein, bacterial membrane-associated
complexes that attach to the recipient cell and bring it into close proximity
with the host. They have not been well studied. This research examines
the protein-protein interactions involved in type IV transporters using
yeast two-hybrid assays and will construct a high-resolution protein map
and determine the specific amino acid residues required for interaction.
The functional significance of the peptide interactions will be confirmed
in-vivo, and conservation of the peptide functions in other transporter
systems will be examined. This research may be valuable to genetic engineering
for industrial and agricultural uses, as well as identification of targets
for disease intervention.

Cheryl Whistler

University of Hawaii

Animal Development

0074400

The role of the GacA/S Sensory
System of the Marine Bacterium Vibrio fischeri During Symbiotic Association
of the Bacterium with its Animal Host, the Hawaiian Bobtail Squid

This research explores how
the symbiotic bacterium, V. fischeri, regulates association with its squid
host, Euprymna scolopes. A sensory system, GacA/S which is involved in
the virulence of pathogens, is experimentally mutated and the resulting
symbiotic traits of the bacterium are assessed. The mutant bacterium is
evaluated for its ability to associate with and influence normal development
of the squid.

Alexandra Worden

Scripps Institution of Oceanography

Ecological and Evolutionary
Physiology

0074392

Diversity and Physiology
of Extemely Small Algae

Extremely small algae, otherwise known as picoeukaryotes (0.2-2micrometers), have been recorded as abundant in the worlds oceans since the early 1980s. Unfortunately little is known about them probably due to the fact that they are not well suited to characterization by microscopy or flow cytometry. The proposed work will explore both the diversity and physiology of these unique organisms. Diversity will be assessed in a marine ecosystem using phylogenetic libraries based on the 18S rRNA gene. In addition, two newly isolated strains will be characterized both phylogenetically and morphologically. In order to gain a better understanding of the physiology of these organisms, and their ability to co-exist with photosynthetic prokaryotic counterparts, preferences and mechanisms for nitrogen utilization will assessed. Growth under different nitrogen conditions will be measured and the molecular genetics of their nitrate transporters characterized. A full length cDNA will be generated and employed for the development of an antibody to the nitrate transporter for further elucidation of cellular response to changing nitrogen conditions. This type of approach should allow a high degree of sensitivity in analyzing growth regulating environmental factors.